US6134024A
Expired / Lapsed
US
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Dithering device
Assignee: Oki Electric Industry Co Ltd
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Filing: 1998-08-25
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Granted: 2000-10-17
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Expires: 2018-08-25
Abstract
Abstract A dithering device converts a multi-gradation image into a binary image by comparing, in sequence, values of pixels forming the multi-gradation image with threshold values of corresponding elements forming a dither matrix. For determining the element corresponding to the pixel, the dithering device uses an array representing a relationship between a first group of positions of the elements to be used currently and a second group of positions of the elements to be used next. By referring to the array, the dithering device determines the position of the element from the second group based on the position of the element in the first group so as to compare the next pixel with the threshold value of the determined element.
Inventors
- 👤 Hideki Miura
- 👤 Koji Urasawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 17:49
CPC Classifications
H; H04; H04N; H04N1/00; H04N1/40; H04N1/405; H04N1/4055; H04N1/4058
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
162 words
A dithering device for converting a multi-gradation image into a binary image by comparing, in sequence, values of pixels forming the multi-gradation image with threshold values assigned to elements forming a dither matrix which elements are logically located at positions corresponding to positions of the pixels, said dithering device comprising: a storage circuit storing an array representing a relationship between a first group of the positions of the elements each corresponding to first one of the pixels and a second group of the positions of the elements each corresponding to second one of the pixels, said second one of the pixels compared next to the corresponding first one of the pixels; and a determination circuit which, by referring to said array, determines the position of the element from said second group based on the position of the element in said first group for comparing said second one of the pixels with the threshold value of the element determined by said determination circuit.
Claim 2
Dependent Claim
162 words
A dithering device for converting a multi-gradation image into a binary image by comparing, in sequence, values of pixels forming the multi-gradation image with threshold values assigned to elements forming a dither matrix which elements are logically located at positions corresponding to positions of the pixels, said dithering device comprising: a storage circuit storing an array representing a relationship between a first group of the positions of the elements each corresponding to first one of the pixels and a second group of the positions of the elements each corresponding to second one of the pixels, said second one of the pixels compared next to the corresponding first one of the pixels; and a determination circuit which, by referring to said array, determines the position of the element from said second group based on the position of the element in said first group for comparing said second one of the pixels with the threshold value of the element determined by said determination circuit.
Claim 3
Dependent Claim
21 words
The dithering device according to claim 1, further comprising a producing circuit for producing said array based on said dither matrix.
Claim 4
Dependent Claim
24 words
The dithering device according to claim 1, wherein said storage circuit stores in advance said array which is produced based on said dither matrix.
Claim 5
Dependent Claim
22 words
The dithering device according to claim 1, wherein the relationship of said array recurs per cycle of the number of said elements.
Claim 6
Dependent Claim
260 words
A dithering device for converting a multi-gradation image into a binary image by comparing, in sequence, values of pixels forming the multi-gradation image with threshold values assigned to elements forming a dither matrix which elements are logically located at positions corresponding to positions of the pixels, said dithering device comprising: a first storage circuit storing a first array representing a relationship between a first group of the positions of the elements each corresponding to first one of the pixels and a second group of the positions of the elements each corresponding to second one of the pixels, said second one of the pixels compared next to the corresponding first one of the pixels in an X-axis direction of the multi-gradation image; a second storage circuit storing a second array representing a relationship between a third group of the positions of the elements each corresponding to third one of the pixels and a fourth group of the positions of the elements each corresponding to fourth one of the pixels, said fourth one of the pixels compared next to the corresponding third one of the pixels in a Y-axis direction of the multi-gradation image; and a determination circuit which, by referring to one of said first and second arrays, determines the position of the element from one of said second and fourth groups based on the position of the element in one of said first and third groups for comparing one of said second and fourth ones of the pixels with the threshold value of the element determined by said determination circuit.
Claim 7
Dependent Claim
260 words
A dithering device for converting a multi-gradation image into a binary image by comparing, in sequence, values of pixels forming the multi-gradation image with threshold values assigned to elements forming a dither matrix which elements are logically located at positions corresponding to positions of the pixels, said dithering device comprising: a first storage circuit storing a first array representing a relationship between a first group of the positions of the elements each corresponding to first one of the pixels and a second group of the positions of the elements each corresponding to second one of the pixels, said second one of the pixels compared next to the corresponding first one of the pixels in an X-axis direction of the multi-gradation image; a second storage circuit storing a second array representing a relationship between a third group of the positions of the elements each corresponding to third one of the pixels and a fourth group of the positions of the elements each corresponding to fourth one of the pixels, said fourth one of the pixels compared next to the corresponding third one of the pixels in a Y-axis direction of the multi-gradation image; and a determination circuit which, by referring to one of said first and second arrays, determines the position of the element from one of said second and fourth groups based on the position of the element in one of said first and third groups for comparing one of said second and fourth ones of the pixels with the threshold value of the element determined by said determination circuit.
Claim 8
Dependent Claim
16 words
The dithering device according to claim 5, wherein said dither matrix has an essentially Z shape.
Claim 9
Dependent Claim
27 words
The dithering device according to claim 6, wherein the relationship of each of said first and second arrays recurs per cycle of the number of said elements.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2003-10-17 | 2004-04-17 | 2004-10-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2007-10-17 | 2008-04-17 | 2008-10-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2011-10-17 | 2012-04-17 | 2012-10-17 | $7700.00 | Window Closed / Lapsed |